LAPACK 3.12.1
LAPACK: Linear Algebra PACKage
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◆ ilaslr()

integer function ilaslr ( integer m,
integer n,
real, dimension( lda, * ) a,
integer lda )

ILASLR scans a matrix for its last non-zero row.

Download ILASLR + dependencies [TGZ] [ZIP] [TXT]

Purpose:
!> !> ILASLR scans A for its last non-zero row. !>
Parameters
[in]M
!> M is INTEGER !> The number of rows of the matrix A. !>
[in]N
!> N is INTEGER !> The number of columns of the matrix A. !>
[in]A
!> A is REAL array, dimension (LDA,N) !> The m by n matrix A. !>
[in]LDA
!> LDA is INTEGER !> The leading dimension of the array A. LDA >= max(1,M). !>
Author
Univ. of Tennessee
Univ. of California Berkeley
Univ. of Colorado Denver
NAG Ltd.

Definition at line 75 of file ilaslr.f.

76*
77* -- LAPACK auxiliary routine --
78* -- LAPACK is a software package provided by Univ. of Tennessee, --
79* -- Univ. of California Berkeley, Univ. of Colorado Denver and NAG Ltd..--
80*
81* .. Scalar Arguments ..
82 INTEGER M, N, LDA
83* ..
84* .. Array Arguments ..
85 REAL A( LDA, * )
86* ..
87*
88* =====================================================================
89*
90* .. Parameters ..
91 REAL ZERO
92 parameter( zero = 0.0e+0 )
93* ..
94* .. Local Scalars ..
95 INTEGER I, J
96* ..
97* .. Executable Statements ..
98*
99* Quick test for the common case where one corner is non-zero.
100 IF( m.EQ.0 ) THEN
101 ilaslr = m
102 ELSEIF( a(m, 1).NE.zero .OR. a(m, n).NE.zero ) THEN
103 ilaslr = m
104 ELSE
105* Scan up each column tracking the last zero row seen.
106 ilaslr = 0
107 DO j = 1, n
108 i=m
109 DO WHILE((a(max(i,1),j).EQ.zero).AND.(i.GE.1))
110 i=i-1
111 ENDDO
112 ilaslr = max( ilaslr, i )
113 END DO
114 END IF
115 RETURN
integer function ilaslr(m, n, a, lda)
ILASLR scans a matrix for its last non-zero row.
Definition ilaslr.f:76
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